Work with difference quotient, except using y rather than h which is how the difference quotient is typically presented.[br][br]See[br][url]https://www.khanacademy.org/math/calculus/differential-calculus/secant-line-slope-tangent/v/slope-of-a-line-secant-to-a-curve[/url][br]for videos about why we will need this topic.